Pin-tumbler lock



M. FALK.

PIN TUMBLER LOCK.

APPLICATION FILED MAR, 10. 1921.

' 1,414,348. I Patentd May 2,1922.

36 Inventor:

MDRRis FALK 27 .1. A Byfifww itor'ne ys.

MORRIS FALK, OF LEOMINSTER, MASSACHUSETTS.

PIN-TUMBLER LOCK.

Specification of Letters Patent.

Patented May 2,1922.

T 0 all wlumait may concern Be it known that I, Moiuus FALK, a citizen ot' the United States. residing at Leominster, in the county of Worcester and State of Massachusetts. have invented a. new and useful Pin-Tumbler Lock, of which the followin is a specification.

This invention relates to a lock of the pin tumbler type. These locks have been regarded as safe heretofore but now instru ments have been invented by which they can be picked very readily. he principle on which these instruments work is that the operator places a blade in the key-hole with which he can force up the first pin and then turn the cylinder very slightly so as to get the hole in the cylinder slightly out of registration with the pin hole in the lock frame. This prevents the pin from dropping down, at least temporarily. Then while holding the cylinder in that position he forces another blade in and carefully raises the second pin. The operation requires skill but it can be done so as to get both pins up where they will be held from dropping down by the slight turn ofthe cylinder. He then works the other pins in the same way and by using one blade to hold the cylinder and a second one for manipulating the pin on which he is working he succeeds in getting them all out of the way and is then free to turn the cylinder and release the door or the like which is held by it.

This invention is designed to prevent that operation and it constitutes mainly the division of the cylinder into two parts independently rotatable and the removal of the surfaceon which the tools above mentioned have to rest inorder to get the necessary leverage.

Reference is to be hadto the accompanying drawings in which Fig. 1 is a side view of a pin tumbler lock constructed in accordance with this invention and shown partly in central longitudinal section;

Fig. 2 is a sectional view on the line 22 of Fig. 1; I

Fig. 3 is a sectional view on the line 33 of Fig. 1, and

Fig. 4 is a bottom plan of the rear cylinder.

The lock is shown as provided with the usual front plate 10 and frame 11. These are of the ordinary shape or can be made in any desired way. The frame 11 is proting the latches or other devices controlled by the lock.

Except for a feature which will be described now, the cylinder and the other parts above described are of the usual ordinary construction. The whole cylinder in which several pins engage is composed of two-parts 20 and 21 These cylinders are located end to end in axial alignment but out of actual contact. The cylinder 20 is shown herein as a little shorter than the cylinder 21 but that is not essential. They are located in the same passage in the frame 11 and are separated at their adjacent ends enough so that one cannot be turned frictionally by the other.

It is to. be noted that at the bottom of the rear cylinder 21 there is a longitudinal passage 23 communicating with the bottom of the key-hole 24. This is an impoi tent feature as will appear.

Also extending around each of the cylinders is a circumferential groove 25. This is for the reception of two ends 28 and 29 of a plate 26. This plate is fastened to the frame 11 by a screw 27 and its integral ends are curved attheir tops and project into the two grooves 25. Any other means may be employed for preventing longitudinal motion of the two cylinders 20 and 21 and thus keeping them out of contact as well as pre venting their displacement in any direction.

This lock is, of course, operated by the usual key in the usual way to turn the bar 19. If, however, any one attempts to pick the look by the instruments above mentioned he will encounter difficulty in the first place by the fact that his tools will find no surface on which to rest at the bottom of the keyhole. This is due to the presence of the passage 23. Consequently, he cannot get the necessary leverage and will have much more than the usual difiiculty in raising the first pin. But if he does succeed in raising that, and, in fact, in raising all the pins of the first cylinder 20, he will then have this cylinder loose so that-he can turn it around at r of the registering position shown in ig 'tioned.

'will. Now, however, he has lost his chance to hold the second cylinder 21 slightl out 3 while he raises the pins in that c linder. Of course, the cylinder 20 being ree to turn cannot be used 'to apply pressure to hold the cylinder 21 out of position and he is confronted notonly with this difficulty but by the fact that his tools cannot get an leverage at the bottom of the key-hole o the second cylinder. This prevents his picking this look with the instruments above men- Although I have illustrated and described only 'a sin 1e form of the invention, I am aware of t .e fact that modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore, I do not' wish to be limited to all the details of construction herein shown and described but what I do claim 18 1. In a pin tumbler lock, the combination of a pair of independently rotatable cylinders arranged'end to end out of contact, each having pin holes for locking pinsand havin a circumferential groove, a frame rovide with a corresponding number of spring pressed locking pins, and a plate having its ends projecting into said grooves for holding said cylinders independently against longitudinal motion.

2. In a pintumbler lock, the combination of a pair of cylinders placed end to end, each of said cylinders having a row of holes for locking pins, a frame provided with a single row of locking pins,-some for en agement in said holes in one cylinder, an t e rest for engagin in the holes of the other cylinder, one 0 said cylinders having a longitudinal key-hole intersecting the row of pin holes and being provided with a longitudinal space exten'di'ng under the keyhole whereby the bottom of the key-hole is left entirely open to prevent tampering with the pins entering the holes of the other cylinder.

3. In a pin tumbler lock, the combination of a frame having a cylindrical passage therein, a pair of cylinders located end to end in said passage, each having a row of holes for lockingpins, and a row of spring pressed locking pins for engagement in said holes, each cylinder having a longitudinal key-hole intersecting the row of pin holes and the frame being provided with a longitudinal space extending under the key-hole in the rear cylinder only, whereby the bottom of the key-hole is leftentirely open to prevent furnishing a base for use in tampering with the other cylinder.

In testimony whereof I have hereunto aflixed my signature.

MORRIS FALK. 

